1. Field of the Invention
The present invention relates to a couch apparatus for medical use, such as use with a magnetic resonance imaging apparatus, an x-ray CT scanner, or [and] a SPECT apparatus.
2. Description of the Related Art
For medical use, this type of couch apparatus is situated near an apparatus for diagnosis or treatment, and is designed to move a desired portion of a subject to the apparatus for diagnosis or treatment. The couch apparatus generally comprises a lower base fixed on the floor, an elevating mechanism mounted on the lower base, an upper base fixed on the elevating mechanism, a tabletop installed slidably on the upper base, and a tabletop sliding mechanism.
A conventional couch apparatus will now be described with reference to FIG. 1. FIG. 1 is a perspective view of an upper base, a tabletop and a tabletop sliding mechanism of the couch apparatus. As shown in FIG. 1, a first pulley 12 is provided on the side face of one end portion of upper base 10, and a second pulley 14 is provided on the side face of the other end portion of the upper base 10. An endless belt 16 is passed over the first and second pulleys 12 and 14. The upper base 10 is provided with a gear mechanism 22 including an AC motor 18 and a clutch 20. The gear mechanism 22 is driven by the AC motor 18 to run the endless belt 16 in a forward direction and a reverse direction, as indicated by a double-headed arrow 24.
The upper base 10 is provided with a pair of guide rails 26 (shown in FIG. 3), each having a substantially C-shaped cross section. The guide rails 26 extend in the longitudinal direction of the upper base 10. A roller mechanism 28 (shown in FIG. 2) is provided so as to be slidable along the guide rails 26. A table-top 30 (shown in FIG. 2) is situated on the upper base 10, and the roller mechanism 28 is fixed on the lower surface of the tabletop 30. One end of a coupling member 34 is fixed to the roller mechanism 28, and the other end thereof is fixed to the endless belt 16.
FIG. 2 is a cross-sectional view taken along line II--II in FIG. 1. Referring to FIG. 2, the structure of the tabletop sliding mechanism including the upper base 10, tabletop 30 and roller mechanism 28 of the couch apparatus will be clearly understood. In FIG. 2, reference numeral 10A denotes flanges formed along the longitudinal axis of the upper base 10. The flanges 10A function to cover the endless belt 16.
In the above structure, the AC motor 18 is driven by a driver and a controller (both not shown) to run the endless belt 16 in the forward and reverse directions indicated by the arrow 24. When the endless belt 16 runs forward, the tabletop 30 approaches an apparatus body (not shown). When the belt 16 runs in a reverse direction, the tabletop 30 moves away from the apparatus body. The direction of movement of the belt 16 is switched by the clutch 20.
The above-described conventional couch apparatus for medicine has the following drawbacks. When the tabletop 30 is moved, such mechanical components as guide rails 26 mounted on the upper base 10, endless belt 16 and pulleys 12 and 14 provided on the side face, and coupling member 34 coupled to the endless belt 16 are exposed to a subject resting on tabletop 30. Thus, the subject may have discomfort. In addition, the exposure of the mechanical components degrades the external appearance of the medical apparatus.
When tabletop 30 moves closest to the apparatus body, the fingers of a subject resting on tabletop 30 may inadvertently be put in gaps 32 between the flanges 10A and the guide rails 26, and the fingers may be fractured.